mpfab TURBO KIT HELP!!!!!! could help all us diy guys

Anyone that has this mpfab turbo kit, if you could look at turbo and tell us what it is. ie: garrett t15 a/r 35... etc.

im curious as to type (brand), a/r ratio, overall size of inlets/outlets. I couldn't tell if they were oil cooled or water cooled. of coarse mpfab gives very very veag info when asked about their kit.

Any help for all of us diy guys would be great.

all turbos i find right now are interal wastegate (A ok for this application) but are set at 10-13psi which i believe is gunna be a little much for our wr250x.

Also anyone that wants to know what a mpfab kit costs its $1800 (emailed them 1 to 2 weeks ago). their kits are for 6psi


thanks for all the help

wr250kid wrote:

all turbos i find right now are interal wastegate (A ok for this application) but are set at 10-13psi which i believe is gunna be a little much for our wr250x.

That's easy enough to deal with. A new actuator is about $25 for whatever pressure you want. I've also known folks to put a "helper" spring on the wastegate to lower the pressure, but it tends to make it leak a bit so spool isn't as good.

Why copy their kit? Are you wanting more top end, mid range, or bottom end? Do you care if the top end suffers to gain some low end? Do you plan to intercool?

Turbo systems aren't the black magic that people make them out to be, just takes a little research. The biggest mistake most folks make is that they go too small on the exhaust housing to get faster spool and too big on the compressor trying to make top end power. Finding the perfect balance just means knowing what you have, what you want, and how to read compressor maps.

*edit* Improper use of there/their. I'm a retard.

well ive done research for car setups using calculations for cfm,..etc but it tough to find any specs on cfm rating of head etc. i kind of want to stunt so a turbo is useless but when i saw that you can get a gt15 for 200 bucks or so. i can't imaging some piping would cost that much i figure it cost a max of $800 to build a kit. i would perfer more bottom end but the kicker is i don't want the turbo to get to hot and "coke" the oil. i would prefer to run a intercooler but you'd have to run so much tubing i'm sure you'd lose boost. i know you can minipulate these issues with a/r ratio, compressor wheel, ball bearing turbos etc. i guess the biggest concern is oil getting to hot, cause i prefer to ride more then 20min at a time, and it all in town on/off gas constantly

wr250kid wrote:

well ive done research for car setups using calculations for cfm,..etc but it tough to find any specs on cfm rating of head etc.

The head flow values really don't matter much in turbo design. Obviously a better flowing head will result in more power with less boost and it does affect your turbo sizing. All those numbers go right out the window once you compress the air charge though. For them to have any real value you'd have to know the temperature and density of the air during that test (provided by any reputable head shop), but also know what the temperature out of your turbo will be... which is a crap shoot at best until you've built your kit. You have to make so many assumptions to utilize head flow in the turbo kit design that the value of the extra effort is lost. If you know the stock power and the stock displacement you can get a pretty fair approximation of volumetric efficiency (which will vary depending on your place in the power band just like the turbo efficiency). That's usually a better starting place than head flow in my opinion.

wr250kid wrote:

I can't imaging some piping would cost that much i figure it cost a max of $800 to build a kit.

That sounds about right depending on if you do the fab work yourself or have it done for you. The last kit I built for a car cost me roughly that much including an intercooler, nice t-bolt clamps, used garrett turbo ($150), and SS oil fittings/drain hose. If you couldn't build a system minus intercoolor on a bike for that you did something wrong. The silicone elbows in the piping add up fast as do the t-bolt clamps. Silicone joint + 2 t-bolt clamps makes it roughly $50-60 per flex joint. If you don't have the skill or the equipment to do your own fabrication you'd be hard pressed to do it for under $800.

wr250kid wrote:

i would perfer more bottom end but the kicker is i don't want the turbo to get to hot and "coke" the oil.

I've run oil cooled only turbos pretty damn hard and although you will certainly cook the oil it's not that bad in a non endurance racing situation. I just changed the oil every 2000-3000 miles (synthetic) depending on how clean it looked on the dipstick. That was in a high strung 1.8L making 280whp as a daily driver. From my experience folks that actually burn up their turbos and pull it apart to find oil clogged up... had a clogged return line the kept oil from circulating properly. If you're worried about it, a water cooled center section is pretty easy to plumb in.

wr250kid wrote:

i would prefer to run a intercooler but you'd have to run so much tubing i'm sure you'd lose boost. i know you can minipulate these issues with a/r ratio, compressor wheel, ball bearing turbos etc.

If you're losing boost you either have a leak or the air charge has lost heat. Power is made by mass flow rate of air so a loss of heat won't hurt you (it's actually helpful that's why you want an intercooler). I think Maximum Boost mentioned an experiment done where he ran intercooler piping crazy long and crazy short and there was no measurable difference in turbo lag, spool, or power. The main reason for keep it short is weight reduction.

My biggest concern with an intercooler would be placement. There really isn't a good place to put one on our bikes that isn't easy to damage in a crash (which I do now and then). I think you're best bet would be to swap to a wr450 style coolant overflow can, move your fuses, and try to mount one opposite of the radiator.

i agree an intercooler on the other side of radiator where the overflow is would be sweet or just put it where the engine guard would be on front, rocks would tear it apart in short time but if you built a protector(screen or something) it may last. again runing pipe to it would be ugly as fuck and likely to just make the setup look like a cluster f***. i know the mpfab guys say they run there kits for 2 years or what not but they don't describe the riding. like is it 20min cruse around town then sit at a parking lot for 10 min then another 20 min ride then 10min to talk to girls then 20 min of riding lol you kno. i'm sure it will hold up just fine i guess when the intake pipe gets so hot that you cant stand it you stop for a bit.

You think a gt15 would be to much turbo? i would have to get new actuator for turbo wastegate no way i'd run 13lbs

I'm not too familiar with turbos that small. GT25 is the smallest series I've messed with.

Just a quick glance at the maps it would be a close call between a GT12 or GT15.

I'd likely go with the GT1544 @ 14psi. Should be good for around 65 HP and would still spool pretty quick.

Pretty sure you need to be looking at the IHI turbos. The 3 series.... I think it's RHB3 or similar.

New turbos are not cheap, nor is the piping, controller, labor etc. I think his price is fair.
That said, I don't like the location, too easy to smack/damage in a crash or in the woods. If it were mounted under the tail that would be better for my uses.